CHARLESTON, SC (WCSC) - Loud booms and shaking across the Charleston area Monday afternoon had people a little jumpy.

Three big booms were reported late Monday afternoon. The reports came from people in different parts of the metro area.

A Mt. Pleasant man said it felt like a truck hit his house. Vacationers from Canada reported hearing and feeling a series of loud booms at Folly Beach.

"They sounded and felt like muffled explosions. Others on the beach appeared as unsettled as we were," said one Lowcountry resident. "The last few we felt once we had returned to our condo. The sound made the light in the dining room rattle."

"Stuff like this normally does not bother me, but this was over the top," says one Mt. Pleasant resident. "I could actually see the window frame move."

Earthquake experts at the College of Charleston said there was no evidence of seismic activity.

Dr. Erin Beutel with the college says they had several people double check, because they know people are concerned. Dr. Beutel says she speculates they were sonic booms, but because we don't know about military activities it is only speculation.

Over the past few decades, folks in Charleston have occasionally heard unexplained booms which were determined to be atmospheric rather than seismic.